# US 2021/0243058 A1 · Fixed-length probabilistic amplitude shaping

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- Number: US 2021/0243058 A1
- Document ID: US20210243058A1
- Status: Published application
- Kind: A1
- Application number: 17/163,771
- Filed: 2021-02-01
- Published: 2021-08-05
- Earliest claimed: 2020-02-03
- Assignees: QUALCOMM Incorporated
- Applicants: QUALCOMM Incorporated
- Inventors: Dung Ngoc DOAN; Lin YANG; Bin TIAN
- Web page: https://patentgrep.com/patent/US20210243058A1

## CPC

- H04L 1/0042: {Encoding specially adapted to other signal generation operation, e.g. in order to reduce transmit distortions, jitter, or to improve signal shape (H04L1/0067 takes precedence)}
- H04L 27/04: Modulator circuits; Transmitter circuits
- H04L 1/0045: {Arrangements at the receiver end}
- H04L 1/0057: {Block codes (H04L1/0061, H04L1/0064 take precedence)}
- H04L 1/0063: {Single parity check}
- H04L 27/0014: {Carrier regulation (of chaotic carriers H04L27/001; for multicarrier receivers H04L27/2657)}
- H04L 27/06: Demodulator circuits; Receiver circuits
- H04L 27/3405: {Modifications of the signal space to increase the efficiency of transmission, e.g. reduction of the bit error rate, bandwidth, or average power}
- H04L 27/36: Modulator circuits; Transmitter circuits
- H04L 2027/0083: {Signalling arrangements}
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

This disclosure provides methods, devices and systems for encoding data for wireless communication to achieve probabilistic amplitude shaping. In some implementations, a transmitting device may achieve a fixed information block length (N), at least in part, by iteratively encoding the information bits until the number of amplitude-shaped bits combined with the number of unshaped bits is greater than or equal to a maximum payload length. For example, the maximum payload length may be equal to N. If the resulting number of amplitude-shaped bits plus the number of unshaped bits is less than N, the transmitting device may add one or more padding bits to the information block to achieve the fixed information block length.

## Claims

### Claim 1

A method for wireless communication by a wireless communication device, comprising:
obtaining a first information block that includes a fixed number (N1) of information bits;
performing a first encoding operation on one or more of the information bits that produces a number (LS) of amplitude-shaped bits;
arranging the LS amplitude-shaped bits into a second information block that includes a number (LUS) of the information bits from the first information block, the sum of LS and LUS being less than or equal to a fixed amount (N2);
selectively adding one or more padding bits to the second information block so that a length of the second information block is equal to N2;
adding, to the second information block, one or more signaling bits indicating the number of amplitude-shaped bits in the second information block;
performing a second encoding operation on the second information block that produces one or more codewords, each codeword including a respective subset of bits of the second information block and one or more parity bits resulting from the second encoding operation;
arranging the subsets of bits of the second information block and the parity bits into a plurality of symbols, each symbol having an amplitude based on the respective bits arranged in the symbol, the first encoding operation producing the amplitude-shaped bits so that the amplitudes of the plurality of symbols have a non-uniform distribution; and
transmitting a wireless packet, including the plurality of symbols, to at least one receiving device.

### Claim 2 (depends on 1)

The method of claim 1, wherein the performing of the first encoding operation comprises:
iteratively selecting, from a look-up table (LUT), a pattern of bit values that matches a subset of the information bits, the LUT storing a plurality of patterns of bit values corresponding to a respective plurality of patterns of amplitude-shaped bits, the plurality of patterns of amplitude-shaped bits including the pattern of amplitude-shaped bits corresponding to the selected pattern of bit values.

### Claim 3 (depends on 2)

The method of claim 2, wherein the iterative selecting of the pattern of bit values comprises:
determining, for each iteration, whether the selection of a first pattern of bit values matching a first subset of the information bits would cause the sum of LS and LUS to be greater than N2.

### Claim 4 (depends on 3)

The method of claim 3, wherein the iterative selecting of the pattern of bit values further comprises:
terminating the first encoding operation, without selecting the first pattern of bit values, responsive to determining that selecting the first pattern of bit values would cause the sum of LS and LUS to be greater than N2.

### Claim 5 (depends on 3)

The method of claim 3, wherein the iterative selecting of the pattern of bit values further comprises:
determining whether the selection of a second pattern of bit values matching a second subset of the information bits would cause the sum of LS and LUS to be less than or equal to N2 responsive to determining that selecting the first pattern of bit values would cause the sum of LS and LUS to be greater than N2.

### Claim 6 (depends on 5)

The method of claim 5, wherein the second subset of the information bits is larger than the first subset of the information bits.

### Claim 7 (depends on 5)

The method of claim 5, wherein the iterative selecting of the pattern of bit values further comprises:
selecting the second pattern of bit values, in lieu of the first pattern of bit values, responsive to determining that the resulting sum of LS and LUS would be less than or equal N2; and
terminating the first encoding operation responsive to selecting the second pattern of bit values.

### Claim 8 (depends on 2)

The method of claim 2, wherein the adding of the one or more signaling bits comprises:
determining a number (LPAM) of symbols associated with the amplitude-shaped bits;
determining an estimated number of amplitude-shaped bits associated with the wireless packet based on a length of each pattern of amplitude-shaped bits in the LUT; and
determining a number (LEST) of symbols associated with the estimated number of amplitude-shaped bits, the one or more signaling bits representing a value equal to the difference between LPAM and LEST.

### Claim 9 (depends on 1)

The method of claim 1, wherein the adding of the one or more signaling bits comprises:
determining a number (LPAM) of symbols associated with the amplitude-shaped bits, the one or more signaling bits representing a value equal to LPAM.

### Claim 10 (depends on 1)

The method of claim 1, wherein the adding of the one or more signaling bits comprises:
determining a number (LPAM) of symbols associated with the amplitude-shaped bits;
determining a mean number of amplitude-shaped bits encodable based on the first encoding operation given N1 information bits; and
determining a number (LMEAN) of symbols associated with the mean number of amplitude-shaped bits, the one or more signaling bits representing a value equal to the difference between LPAM and LMEAN.

### Claim 11 (depends on 1)

The method of claim 1, wherein the adding of the one or more signaling bits comprises:
determining a number of symbols associated with the information bits in the second information block, the one or more signaling bits representing a value equal to the number of symbols associated with the information bits in the second information block.

### Claim 12 (depends on 1)

The method of claim 1, wherein the one or more signaling bits represent a value equal to a number of padding bits included in the second information block.

### Claim 13

A wireless communication device comprising:
at least one modem;
at least one processor communicatively coupled with the at least one modem; and
at least one memory communicatively coupled with the at least one processor and storing processor-readable code that, when executed by the at least one processor in conjunction with the at least one modem, is configured to:
obtain a first information block that includes a fixed number (N1) of information bits;
perform a first encoding operation on one or more of the information bits that produces a number (LS) of amplitude-shaped bits;
arrange the LS amplitude-shaped bits into a second information block that includes a number (LUS) of the information bits from the first information block, the sum of LS and LUS being less than or equal to a fixed amount (N2);
selectively add one or more padding bits to the second information block so that a length of the second information block is equal to N2;
add, to the second information block, one or more signaling bits indicating the number of amplitude-shaped bits in the second information block;
perform a second encoding operation on the second information block that produces one or more codewords, each codeword including a respective subset of bits of the second information block and one or more parity bits resulting from the second encoding operation;
arrange the subsets of bits of the second information block and the parity bits into a plurality of symbols, each symbol having an amplitude based on the respective bits arranged in the symbol, the first encoding operation producing the amplitude-shaped bits so that the amplitudes of the plurality of symbols have a non-uniform distribution; and
transmit a wireless packet, including the plurality of symbols, to at least one receiving device.

### Claim 14 (depends on 13)

The wireless communication device of claim 13, wherein the performing of the first encoding operation comprises:
iteratively selecting, from a look-up table (LUT), a pattern of bit values that matches a subset of the information bits, the LUT storing a plurality of patterns of bit values corresponding to a respective plurality of patterns of amplitude-shaped bits, the plurality of patterns of amplitude-shaped bits including the pattern of amplitude-shaped bits corresponding to the selected pattern of bit values.

### Claim 15 (depends on 14)

The wireless communication device of claim 14, wherein the iteratively selecting comprises:
determining, for each iteration, whether the selection of a first pattern of bit values matching a first subset of the information bits would cause the sum of LS and LUS to be greater than N2.

### Claim 16 (depends on 15)

The wireless communication device of claim 15, wherein the iteratively selecting further comprises:
terminating the first encoding operation, without selecting the first pattern of bit values, responsive to determining that selecting the first pattern of bit values would cause the sum of LS and LUS to be greater than N2.

### Claim 17 (depends on 15)

The wireless communication device of claim 15, wherein the iteratively selecting further comprises:
determining whether the selection of a second pattern of bit values matching a second subset of the information bits would cause the sum of LS and LUS to be less than or equal to N2 responsive to determining that selecting the first pattern of bit values would cause the sum of LS and LUS to be greater than N2.

### Claim 18 (depends on 17)

The wireless communication device of claim 17, wherein the iteratively selecting further comprises:
selecting the second pattern of bit values, in lieu of the first pattern of bit values, responsive to determining that the resulting sum of LS and LUS would be less than or equal N2; and
terminating the first encoding operation responsive to selecting the second pattern of bit values.

### Claim 19

A method for wireless communication by a wireless communication device, comprising:
receiving a wireless packet including a plurality of symbols having a plurality of amplitudes, the plurality of symbols representing a plurality of codeword bits, the plurality of amplitudes having a non-uniform distribution;
arranging the plurality of codeword bits into one or more codewords;
performing a first decoding operation on the one or more codewords that produces one or more respective decoded code blocks, each decoded code block including a plurality of decoded codeword bits and one or more parity bits;
arranging the pluralities of decoded codeword bits into an information block having a fixed length (N2);
detecting one or more signaling bits of the information block based on the fixed length N2 of the information block;
identifying a number (LS) of amplitude-shaped bits in the information block based on a value associated with the one or more signaling bits;
performing a second decoding operation on the amplitude-shaped bits that produces a number (LDS) of de-shaped bits;
parsing a number (LUS) of unshaped bits from the information block based on the number LDS of de-shaped bits and a fixed length (N1) associated with a decoded information block; and
arranging the de-shaped bits and the unshaped bits into the decoded information block having the fixed length N1.

### Claim 20 (depends on 19)

The method of claim 19, wherein the amplitude-shaped bits represent most significant bits (MSBs) of the information block.

### Claim 21 (depends on 19)

The method of claim 19, wherein the sum of LUS and LDS is equal to N2.

### Claim 22 (depends on 21)

The method of claim 21, further comprising:
discarding one or more bits of the information block in excess of LUS.

### Claim 23 (depends on 22)

The method of claim 22, wherein the discarded bits represent least significant bits (LSBs) of the information block.

### Claim 24 (depends on 19)

The method of claim 19, wherein the performing of the second decoding operation comprises:
selecting, from a look-up table (LUT), a pattern of de-shaped bits that matches a subset of the amplitude-shaped bits, the LUT storing a plurality of patterns of de-shaped bits corresponding to a respective plurality of patterns of amplitude-shaped bits, the plurality of de-shaped bits including the selected pattern of de-shaped bits.

### Claim 25 (depends on 24)

The method of claim 24, wherein the identifying of the number of amplitude-shaped bits comprises:
determining an estimated number of amplitude-shaped bits associated with the wireless packet based on a length of each pattern of amplitude-shaped bits in the LUT;
determining a number (LEST) of symbols associated with the estimated number of amplitude-shaped bits;
determining a number (LPAM) of symbols associated with the amplitude-shaped bits based on a difference between LEST and the value associated with the one or more signaling bits; and
determining the number of amplitude-shaped bits associated with LPAM.

### Claim 26 (depends on 19)

The method of claim 19, wherein the identifying of the number of amplitude-shaped bits comprises:
determining a number (LPAM) of symbols associated with the amplitude-shaped bits based on the value associated with the one or more signaling bits; and
determining the number of amplitude-shaped bits associated with LPAM.

### Claim 27 (depends on 19)

The method of claim 19, wherein the identifying of the number of amplitude-shaped bits comprises:
determining a mean number of amplitude-shaped bits decodable based on the second decoding operation given N1 information bits;
determining a number (LMEAN) of symbols associated with the mean number of amplitude-shaped bits;
determining a number (LPAM) of symbols associated with the amplitude-shaped bits based on a difference between LMEAN and the value associated with the one or more signaling bits; and
determining the number of amplitude-shaped bits associated with LPAM.

### Claim 28 (depends on 19)

The method of claim 19, wherein the identifying of the number of amplitude-shaped bits comprises:
determining a number of padding bits included in the information block based on the value associated with the one or more signaling bits; and
determining the number of amplitude-shaped bits based on N2, LUS, and the number of padding bits.

### Claim 29

A wireless communication device comprising:
at least one modem;
at least one processor communicatively coupled with the at least one modem; and
at least one memory communicatively coupled with the at least one processor and storing processor-readable code that, when executed by the at least one processor in conjunction with the at least one modem, is configured to:
receive a wireless packet including a plurality of symbols having a plurality of amplitudes, the plurality of symbols representing a plurality of codeword bits, the plurality of amplitudes having a non-uniform distribution;
arrange the plurality of codeword bits into one or more codewords;
perform a first decoding operation on the one or more codewords that produces one or more respective decoded code blocks, each decoded code block including a plurality of decoded codeword bits and one or more parity bits;
arrange the pluralities of decoded codeword bits into an information block having a fixed length (N2);
detect one or more signaling bits of the information block based on the fixed length N2 of the information block;
identify a number (LS) of amplitude-shaped bits in the information block based on a value associated with the one or more signaling bits;
perform a second decoding operation on the amplitude-shaped bits that produces a number (LDS) of de-shaped bits;
parse a number (LUS) of unshaped bits from the information block based on the number LDS of de-shaped bits and a fixed length (N1) associated with a decoded information block; and
arrange the de-shaped bits and the unshaped bits into the decoded information block having the fixed length N1.

### Claim 30 (depends on 29)

The wireless communication device of claim 29, wherein the amplitude-shaped bits represent most significant bits (MSBs) of the information block.

### Claim 31 (depends on 29)

The wireless communication device of claim 29, wherein the sum of LUS and LDS is equal to N2.

### Claim 32 (depends on 31)

The wireless communication device of claim 31, wherein execution of the processor-readable code is further configured to:
discard one or more bits of the information block in excess of LUS.

### Claim 33 (depends on 32)

The wireless communication device of claim 32, wherein the discarded bits represent least significant bits (LSBs) of the information block.

### Claim 34 (depends on 29)

The wireless communication device of claim 29, wherein the performing of the second decoding operation comprises:
selecting, from a look-up table (LUT), a pattern of de-shaped bits that matches a subset of amplitude-shaped bits, the LUT storing a plurality of patterns of de-shaped bits corresponding to a respective plurality of patterns of amplitude-shaped bits, the plurality of de-shaped bits including the selected pattern of de-shaped bits.